JP7302354B2 - Liquid ejector - Google Patents

Description

The present invention relates to a liquid ejecting apparatus that ejects liquid from nozzles.

As an example of a liquid ejecting apparatus that ejects liquid from nozzles, Patent Document 1 describes an inkjet printer that performs printing by ejecting ink from nozzles. In the inkjet printer described in Patent Document 1, the presence or absence of ink ejection and the ejection direction are individually inspected for each of the plurality of nozzles of the head. Then, if there is a nozzle that does not eject ink, the suction process is executed, and the above inspection is performed again.

JP-A-2006-175849

Here, in the printer of Patent Document 1, it is possible to detect that ink is not ejected from the nozzles only after ink is actually stopped being ejected from the nozzles. That is, it is not possible to detect in advance nozzles that are highly likely to stop ejecting ink in the near future.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid ejecting apparatus capable of detecting in advance nozzles that are highly likely to stop ejecting liquid in the near future.

A liquid ejecting apparatus of the present invention includes a liquid ejecting head having nozzles and a nozzle surface on which the nozzles are formed; a laser irradiation unit that emits laser light in a first direction along the nozzle surface; A laser light receiving unit arranged in one direction with a gap from the laser irradiation unit for receiving the laser light emitted from the laser irradiation unit, and the liquid discharge head are mounted in a direction along the nozzle surface. a carriage that moves in a second direction that intersects with the first direction; and a controller that moves the nozzle in the first direction when the carriage moves in the second direction. and the laser light receiving unit, the control unit outputs a plurality of drive signals to the liquid ejection head at a predetermined drive cycle to eject the liquid from the nozzles, and the A time twice the drive cycle elapses after the drive cycle for outputting the last drive signal from the final ejection time, which is the time at which the liquid is ejected from the nozzle by the last drive signal among the plurality of drive signals. The carriage is moved in the second direction so as to pass the determination position at a predetermined timing within the determination period up to the point in time when the determination is made, the laser irradiation unit is caused to irradiate a laser beam at the predetermined timing, and the predetermined timing is reached. Whether or not the liquid overflows from the nozzle to the nozzle surface is determined based on the amount of laser light received by the laser light receiving portion at the timing.

A liquid ejection apparatus according to the present invention includes a liquid ejection head having a nozzle and a nozzle surface on which the nozzle is formed; a support member for supporting the liquid ejection head; a laser irradiation unit that irradiates a laser beam in a first direction along the nozzle surface to a portion of the surface where the nozzles are formed; a laser light receiving unit arranged on the opposite side of the laser irradiation unit for receiving the laser light emitted from the laser irradiation unit; to output a plurality of drive signals to cause the nozzles to eject the liquid, and from the final ejection time point, which is the time point at which the liquid is ejected from the nozzles by the last drive signal among the plurality of drive signals, to the last drive signal. After the drive cycle for outputting the signal, the laser irradiation unit is caused to emit a laser beam at a predetermined timing within a determination period up to a point in time when twice the drive cycle has elapsed, and the laser light receiving unit is caused to emit a laser beam at the predetermined timing. Based on the light quantity of the laser beam received at , it is determined whether or not the liquid has overflowed from the nozzle to the nozzle surface.

A liquid ejecting apparatus of the present invention includes a liquid ejecting head having nozzles and a nozzle surface on which the nozzles are formed; a laser irradiation unit that emits laser light in a first direction along the nozzle surface; A laser light receiving unit arranged in one direction with a gap from the laser irradiation unit for receiving the laser light emitted from the laser irradiation unit, and the liquid discharge head are mounted in a direction along the nozzle surface. a carriage that moves in a second direction that intersects with the first direction; and a controller, wherein the liquid ejection head is driven by a plurality of drive signals output from the controller in a predetermined drive cycle. and ejecting liquid from the nozzle, and the carriage, when moving in the second direction, passes through a determination position where the nozzle is positioned between the laser irradiation section and the laser light receiving section in the first direction. and, from the final ejection time, which is the time when the liquid is ejected from the nozzle by the last drive signal among the plurality of drive signals, after the drive cycle in which the last drive signal is output, the time is twice the drive cycle. passes the determination position at a predetermined timing within the determination period up to the time when the laser irradiation unit receives the laser beam from the nozzle at the predetermined timing based on the amount of laser light received by the laser light receiving unit. A laser beam is emitted in order for the controller to determine whether or not the liquid has overflowed onto the nozzle surface.

For nozzles that are highly likely to stop ejecting liquid in the near future, after the liquid is ejected from the nozzle, while the meniscus of the liquid in the nozzle remains vibrating, the liquid temporarily flows from the nozzle onto the nozzle surface. It often overflows. When the liquid is ejected from the nozzle, the meniscus vibration of the liquid in the nozzle remains for about the above-described determination period. Therefore, in the present invention, it is determined at a predetermined timing within the determination period based on the amount of laser light received by the laser light receiving section whether or not the overflow has occurred. This makes it possible to detect in advance nozzles that are highly likely to stop ejecting liquid in the near future.

1 is a schematic configuration diagram of a printer according to a first embodiment; FIG. FIG. 2 is a plan view of the inkjet head of FIG. 1; 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. (a) is a diagram showing the positional relationship among the inkjet head, the cap, the laser irradiation unit, and the laser light receiving unit as seen from the left side in the scanning direction when the carriage is positioned at the position facing the cap; FIG. 5 is a diagram showing the positional relationship among the inkjet head, the cap, the laser irradiation section, and the laser light receiving section viewed from the downstream side in the transport direction when the carriage is positioned at the cap facing position. (a) is a diagram showing the positional relationship between the flushing foam, the laser irradiation section, and the laser light receiving section viewed from the left side in the scanning direction, with the carriage positioned at the position facing the form; FIG. 4 is a diagram showing the positional relationship among the flushing foam, the laser irradiation section, and the laser light receiving section viewed from the downstream side in the conveying direction in a state of being located at the form facing position. 2 is a block diagram showing the electrical configuration of the printer according to the first embodiment; FIG. 6 is a flowchart showing the flow of processing during recording in the first embodiment; (a) is a diagram for explaining the drive cycle of the inkjet head, and (b) is a diagram for explaining the vibration of the ink meniscus in the nozzle. 10 is a flow chart showing the flow of processing during recording in the second embodiment. FIG. 11 is a schematic configuration diagram of a printer according to a third embodiment; 10 is a flow chart showing the flow of processing during recording in the third embodiment. FIG. 16 is a flow chart showing the flow of processing during recording in the fourth embodiment. FIG. FIG. 11 is a schematic configuration diagram of a printer according to a fifth embodiment; FIG. 16 is a flow chart showing the flow of processing during recording in the fifth embodiment; FIG. FIG. 11 is a schematic configuration diagram of a printer according to a sixth embodiment; FIG. 15 is a view of FIG. 15 viewed from the direction of arrow XVI; FIG. 12 is a block diagram showing the electrical configuration of a printer according to the sixth embodiment; FIG. FIG. 16 is a flow chart showing the flow of processing during recording in the sixth embodiment; FIG. 3 is a schematic configuration diagram of a printer according to modification 1; FIG. 18A is a diagram corresponding to FIG. 18 at the time of recording in Modification 2, and FIG. 18B is a diagram corresponding to FIG. 18 at the time of flushing in Modification 2. FIG. (a) is a diagram corresponding to FIG. 18 at the time of recording in Modification 3, and (b) is a diagram corresponding to FIG. 18 at the time of flushing in Modification 3. FIG.

[First embodiment]
A first preferred embodiment of the present invention will be described below.

<Overall configuration of the printer>
As shown in FIG. 1, a printer 1 (“liquid ejection device” of the present invention) according to the first embodiment includes a carriage 2, a sub-tank 3, an inkjet head 4 (“liquid ejection head” of the present invention), a platen 5, It has conveying rollers 6 and 7, a maintenance unit 8, a flushing foam 9 (a "liquid receiver" in the present invention), and the like.

The carriage 2 is supported by two guide rails 11 and 12 extending in the scanning direction (the "second direction" of the invention). The carriage 2 is connected to a carriage motor 86 (see FIG. 6) via a belt (not shown) or the like. When the carriage motor 86 is driven, the carriage 2 moves along the guide rails 11 and 12 in the scanning direction. In the following description, right and left sides in the scanning direction are defined as shown in FIG.

A sub-tank 3 is mounted on the carriage 2 . Here, the printer 1 has a cartridge holder 14 to which four ink cartridges 15 are detachably attached. The four ink cartridges 15 store black, yellow, cyan, and magenta ink (“liquid” in the present invention) from the right side in the scanning direction. The sub-tank 3 is connected to four ink cartridges 15 attached to a cartridge holder 14 via four tubes 13 . As a result, the four color inks are supplied from the four ink cartridges 15 to the sub-tank 3 .

The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the sub-tank 3 . The inkjet head 4 is supplied with the four color inks from the sub-tank 3 . The inkjet head 4 also ejects ink from a plurality of nozzles 10 formed on a nozzle surface 4a, which is the lower surface thereof. More specifically, the nozzle surface 4a is a surface parallel to the scanning direction and the conveying direction perpendicular to the scanning direction (the "first direction" of the present invention). That is, the scanning direction and the transport direction are directions along the nozzle surface 4a. The plurality of nozzles 10 form a nozzle row 19 by being arranged in the transport direction. Four nozzle rows 19 are arranged in the scanning direction on the nozzle surface 4a. Black, yellow, cyan, and magenta inks are ejected from the plurality of nozzles 10, starting from the nozzle row 19 on the right side in the scanning direction.

A platen 5 is arranged below the inkjet head 4 and faces the plurality of nozzles 10 . The platen 5 extends over the entire length of the recording paper P in the scanning direction and supports the recording paper P from below. The transport roller 6 is arranged upstream of the inkjet head 4 and the platen 5 in the transport direction. The transport roller 7 is arranged downstream of the inkjet head 4 and the platen 5 in the transport direction. The transport rollers 6 and 7 are connected to a transport motor 87 (see FIG. 6) via gears (not shown). When the transport motor 87 is driven, the transport rollers 6 and 7 rotate and the recording paper P is transported in the transport direction.

The maintenance unit 8 is for performing a suction purge to discharge the ink inside the inkjet head 4 from the plurality of nozzles 10 as will be described later. The flushing foam 9 is for receiving ink ejected by flushing, as will be described later. The maintenance unit 8 and the flushing foam 9 will be explained later in detail.

<Inkjet head>
Next, the inkjet head 4 will be described in detail. As shown in FIGS. 2 and 3, the inkjet head 4 includes a channel unit 21 and piezoelectric actuators 22 .

<Flow path unit>
The channel unit 21 is formed by stacking four plates 31 to 34 in this order from above. The plates 31-33 are made of a metal material such as stainless steel. The plate 34 is made of a synthetic resin material such as polyimide.

A plurality of nozzles 10 are formed in the plate 34 . The plurality of nozzles 10 form four nozzle rows 19 as described above. The lower surface of the plate 34 serves as the nozzle surface 4 a of the inkjet head 4 . A plurality of pressure chambers 40 are formed in the plate 31 . The pressure chamber 40 has an elliptical planar shape whose longitudinal direction is the scanning direction. Moreover, the plurality of pressure chambers 40 are separate for the plurality of nozzles 10 , and the left end in the scanning direction overlaps the nozzles 10 in the vertical direction. As a result, the plate 31 is formed with a plurality of pressure chambers 40 arranged in the transport direction to form four pressure chamber rows 29 aligned in the scanning direction.

A circular through hole 42 is formed in the plate 32 at a portion vertically overlapping the right end of each pressure chamber 40 in the scanning direction. Further, the plate 32 is formed with a circular through hole 43 at the left end of each pressure chamber 40 in the scanning direction and at a portion overlapping the nozzle 10 in the vertical direction.

The plate 33 is formed with four manifold channels 41 (the "common channel" of the present invention). Four manifold channels 41 correspond to four pressure chamber rows 29 . The manifold channel 41 extends in the transport direction and vertically overlaps the right side portion in the scanning direction of the plurality of pressure chambers 40 forming the corresponding pressure chamber row 29 . Thereby, each pressure chamber 40 communicates with the manifold channel 41 through the through hole 42 . In addition, a supply port 39 is provided at the end of each manifold channel 41 on the upstream side in the transport direction. The inkjet head 4 is connected to the flow channel in the sub-tank 3 at the supply port 39 . As a result, ink is supplied from the supply port 39 to the manifold channel 41 . Circular through-holes 44 are formed in the plate 33 at portions overlapping the through-holes 43 and the nozzles 10 in the vertical direction. Thereby, each nozzle 10 communicates with the pressure chamber 40 via the through holes 43 and 44 .

In the channel unit 21, individual channels 46 are formed by one nozzle 10 and the pressure chamber 40 and the through holes 42 to 44 corresponding to the nozzle 10. As shown in FIG. The channel unit 21 includes a plurality of such individual channels 46 .

<Piezoelectric actuator>
The piezoelectric actuator 22 includes a diaphragm 51 , a piezoelectric layer 52 , a common electrode 53 and a plurality of individual electrodes 54 . The vibration plate 51 is made of a piezoelectric material whose main component is lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate. ing. Note that the vibration plate 51 may be made of an insulating material other than a piezoelectric material, unlike the piezoelectric layer 52 described below.

The piezoelectric layer 52 is made of the piezoelectric material described above, is arranged on the upper surface of the diaphragm 51 , and extends continuously across the plurality of pressure chambers 40 . The common electrode 53 is arranged between the diaphragm 51 and the piezoelectric layer 52 and continuously extends across the plurality of pressure chambers 40 . The common electrode 53 is connected to a power supply circuit (not shown) through a wiring member (not shown) and is held at ground potential.

The plurality of individual electrodes 54 are individual to the plurality of pressure chambers 40 . The individual electrode 54 has an elliptical planar shape that is slightly smaller than the pressure chamber 40 , is arranged on the upper surface of the piezoelectric layer 52 , and overlaps the central portion of the pressure chamber 40 in the vertical direction. The right end portion of the individual electrode 54 in the scanning direction extends to the right side in the scanning direction to a position that does not overlap the pressure chamber 40 in the vertical direction, and the tip portion thereof serves as a connection terminal 54a. A wiring member (not shown) is connected to the connection terminal 54a, and the individual electrode 54 is connected to the driver IC 59 (see FIG. 6) through this wiring member. Then, the driver IC 59 selectively applies either the ground potential or a predetermined driving potential (for example, about 20 V) to each of the individual electrodes 54 .

In addition, corresponding to the arrangement of the common electrode 53 and the plurality of individual electrodes 54 in this way, the portions sandwiched between the common electrode 53 and the individual electrodes 54 of the piezoelectric layer 52 each extend in the thickness direction. Polarized. In the piezoelectric actuator 22 having the structure described above, the portions of the vibration plate 51, the piezoelectric layer 52, and the common electrode 53 that vertically overlap the pressure chambers 40 and the portions formed by the individual electrodes 54 are respectively , the driving element 50 that applies pressure to the ink in the pressure chamber 40 .

Here, in each drive element 50 of the piezoelectric actuator 22 , when the potential of the individual electrode 54 is switched from the ground potential to the drive potential, the potential difference between the individual electrode 54 and the common electrode 53 causes these electrodes of the piezoelectric layer 52 to An electric field is generated in the thickness direction parallel to the polarization direction in the portion sandwiched between the two. Due to this electric field, the above portion of the piezoelectric layer 52 contracts in the horizontal direction, and the portions of the vibration plate 51 and the piezoelectric layer 52 that overlap the pressure chambers 40 in the vertical direction are deformed so as to protrude toward the pressure chambers 40 as a whole. Further, when the potential of the individual electrode 54 is switched from the drive potential to the ground potential, the individual electrode 54 and the common electrode 53 become the same potential, and the portions of the vibration plate 51 and the piezoelectric layer 52 overlapping the pressure chambers 40 in the vertical direction are Return to the state before the above deformation. When the potential of the individual electrode 54 is switched between the ground potential and the drive potential, the deformation of the portions of the diaphragm 51 and the piezoelectric layer 52 overlapping the pressure chambers 40 in the vertical direction causes the volume of the pressure chambers 40 to increase. As a result, pressure is applied to the ink inside the pressure chamber 40 , and the ink is ejected from the nozzle 10 communicating with the pressure chamber 40 .

<Maintenance unit>
Next, the maintenance unit 8 will be explained. As shown in FIG. 1, the maintenance unit 8 includes a cap 61, a suction pump 62, and a waste liquid tank 63. As shown in FIG. The cap 61 is arranged on the right side of the platen 5 within the movement range of the carriage 2 in the scanning direction. When the carriage 2 is positioned at the cap facing position (“first position”, “determination position” of the present invention) on the right side of the scanning direction relative to the platen 5 , the plurality of nozzles 10 face the cap 61 .

Also, the cap 61 can be moved up and down by a cap lifting mechanism 88 (see FIG. 6, "cap switching section" of the present invention). With the carriage 2 positioned at the cap facing position and the plurality of nozzles 10 facing the cap 61, the cap lifting mechanism 88 raises the cap 61 so that the upper end of the cap 61 touches the nozzle surface 4a. The nozzles 10 are brought into close contact with each other, and a capping state in which the plurality of nozzles 10 are covered with the cap 61 is achieved. In addition, when the cap 61 is lowered, the plurality of nozzles 10 are in an uncapping state in which they are not covered with the cap 61 .

Moreover, the cap 61 is not limited to covering the plurality of nozzles 10 by being in close contact with the nozzle surface 4a. The cap 61 may cover the plurality of nozzles 10 by being in close contact with a frame (not shown) arranged around the nozzle surface 4a of the inkjet head 4, for example.

The suction pump 62 is a tube pump or the like, and is connected to the cap 61 and the waste liquid tank 63 through tubes. In the maintenance unit 8, the carriage motor 86 and the cap lifting mechanism 88 are controlled by the control device 80, which will be described later, to achieve the above-described capping state, and then the suction pump 62 is driven so that the plurality of nozzles 10 are ejected from the inkjet head. A suction purge, which is an operation for discharging the ink in 4, can be performed. Ink discharged from the inkjet head 4 is stored in the waste liquid tank 63 .

Here, for the sake of convenience, the cap 61 collectively covers all the nozzles 10, and in the suction purge, the ink in the inkjet head 4 is discharged from all the nozzles 10, but it is not limited to this. do not have. For example, the cap 61 covers the plurality of nozzles 10 forming the rightmost nozzle row 19 that ejects black ink, and the three nozzle rows 19 on the left that eject color ink (yellow, cyan, and magenta ink). and a portion that covers a plurality of nozzles 10 that constitute the . good. Alternatively, for example, the cap 61 may be individually provided for each nozzle row 19 so that ink can be discharged from the nozzles 10 for each nozzle row 19 individually during suction purge.

In addition, in the printer 1, by driving the inkjet head 4 with the carriage 2 positioned at the cap facing position, ink is ejected from the plurality of nozzles 10 toward the cap 61 separately from the ejection of ink toward the recording paper P. It is possible to perform flushing, which is an operation of ejecting ink by pressing.

1, 4(a) and 4(b), the cap 61 has four laser irradiation sections 66 (“first laser irradiation section” of the present invention) and four laser light receiving sections 67. (“first laser light receiving portion” of the present invention) is provided. The four laser irradiation units 66 correspond to the four nozzle rows 19, are located upstream of the nozzle rows 19 in the transport direction, and are arranged in the scanning direction. The four laser light receiving portions 67 correspond to the four nozzle rows 19, are located downstream of the nozzle rows 19 in the transport direction, and are arranged in the scanning direction. And thereby, the laser irradiation part 66 and the laser irradiation part 67 are arrange|positioned at intervals in the conveyance direction. Further, when the carriage 2 is positioned at the cap facing position, the scanning direction positions of the laser irradiation units 66 and the laser light receiving units 67 are the same as the corresponding nozzle rows 19 . Further, the positions of the laser irradiation units 66 and the laser light receiving units 67 in the vertical direction are the same as the nozzle surface 4a.

Each laser irradiation unit 66 irradiates a laser beam L1 in the conveying direction toward the corresponding laser light receiving unit 67 . As a result, when the laser beam L1 is irradiated from the laser irradiation unit 66 while the carriage 2 is positioned at the position facing the cap, the laser beam L1 irradiates a portion of the nozzle surface 4a where the corresponding nozzle row 19 is arranged. pass. The laser light receiving section 67 outputs a signal corresponding to the light quantity of the received laser light L1.

<Flushing foam>
The flushing foam 9 is arranged on the left side of the platen 5 within the movement range of the carriage 2 in the scanning direction. When the carriage 2 is positioned at the form facing position (“second position”, “determination position” of the present invention) on the left side of the scanning direction relative to the platen 5 , the plurality of nozzles 10 face the flushing form 9 . Then, in the printer 1 , the inkjet head 4 is driven while the carriage 2 is positioned at the position facing the form. Flushing, which is an operation of ejecting ink toward the target, can be performed.

As shown in FIGS. 1, 5(a) and 5(b), the flushing foam 9 has four laser irradiation units 68 (“second laser irradiation units” of the present invention) and four laser light receiving units. 69 (“second laser light receiving portion” of the present invention) are provided. The four laser irradiation units 68 correspond to the four nozzle rows 19, are located upstream of the nozzle rows 19 in the transport direction, and are arranged in the scanning direction. The four laser light receiving portions 69 correspond to the four nozzle rows 19, are located downstream of the nozzle rows 19 in the transport direction, and are arranged in the scanning direction. And thereby, the laser irradiation part 68 and the laser irradiation part 69 are arrange|positioned at intervals in the conveyance direction. Further, when the carriage 2 is positioned at the position facing the form, the scanning direction positions of the laser irradiation units 68 and the laser light receiving units 69 are the same as the corresponding nozzle rows 19 . Further, the positions of the laser irradiation units 68 and the laser light receiving units 69 in the vertical direction are the same as the nozzle surface 4a.

Each laser irradiation unit 68 irradiates a laser beam L2 in the conveying direction toward the corresponding laser light receiving unit 69 . As a result, when the laser beam L2 is irradiated from the laser irradiation unit 68 while the carriage 2 is positioned at the position facing the form, the laser beam L2 is projected onto the portion of the nozzle surface 4a where the corresponding nozzle rows 19 are arranged. pass through. The laser light receiving section 69 outputs a signal corresponding to the light quantity of the received laser light L2.

<Electrical Configuration of Printer>
Next, the electrical configuration of the printer 1 will be described. Operations of the printer 1 are controlled by the control device 80 . As shown in FIG. 6, the control device 80 includes a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, a RAM (Random Access Memory) 83, a flash memory 84, an ASIC (Application Specific Integrated Circuit) 85, etc. It controls the operations of the carriage motor 86, the conveying motor 87, the cap lifting mechanism 88, the suction pump 62, the laser irradiation units 66 and 68, and the like. The control device 80 also controls the plurality of drive elements 50 of the inkjet head 4 by controlling the driver IC 59 . However, in order to simplify the description below, it may be said that "the control device 80 controls the inkjet head 4". In addition, a signal corresponding to the amount of received laser light is input to the control device 80 from the laser light receiving units 67 and 69 .

In the control device 80, only the CPU 81 may perform various processes, only the ASIC 85 may perform various processes, or the CPU 81 and the ASIC 85 may cooperate to perform various processes. can be anything. Further, the control device 80 may be one in which one CPU 81 performs processing alone, or may be one in which a plurality of CPUs 81 share the processing. Further, the control device 80 may be one in which one ASIC 85 performs processing alone, or may be one in which a plurality of ASICs 85 share the processing.

<Control during recording>
Next, the control of the control device 80 when recording on the recording paper P in the printer 1 will be described. In the printer 1, when a recording command instructing recording on the recording paper P is input, the control device 80 executes processing according to the flow of FIG.

More specifically, when a recording command is input, the control device 80 first controls the transport motor 87 and the like to supply the recording paper P to the paper feeding unit and transport rollers 6 (not shown). Paper feed operation is performed (S101).

Subsequently, after resetting the value of the variable M to 0 (S102), the controller 80 controls the carriage motor 86 to move the carriage 2 in the scanning direction within the ejection range where the recording paper P is arranged. In addition, the inkjet head 4 is controlled to perform a recording pass process, which is an operation of ejecting ink from a plurality of nozzles 10 toward the recording paper P (S103). At this time, under the control of the control device 80 , the driving elements 50 of the inkjet head 4 are driven by outputting a plurality of driving signals from the driver IC 59 to the inkjet head 4 in a predetermined driving cycle U.

Here, the ejection range is the range in which the platen 5 is arranged at the maximum. Thus, in the first embodiment, the cap 61 is arranged on the right side (“one side” of the present invention) of the ejection range in the scanning direction, and the flushing foam 9 is arranged on the left side of the ejection range (“one side” of the present invention). on the other side”).

Further, in the printer 1, the carriage 2 is positioned at the position facing the cap in a standby state in which recording on the recording paper P is not performed. When recording on the recording paper P, the recording pass processing is repeated as described later. Now, the carriage 2 is moved to the right in the scanning direction.

Subsequently, the control device 80 increases the value of the variable M by 1 (S104). As a result, the value of the variable M corresponds to the number of recording pass processes after recording on the recording paper P is started. Subsequently, the control device 80 determines whether or not the value of the variable M is greater than or equal to the predetermined value Ma (whether or not the flushing condition is satisfied) of the present invention (S105). If the value of the variable M is less than the predetermined value Ma (S105: NO), the process proceeds to S118.

If the value of the variable M is greater than or equal to the predetermined value Ma (S105: YES), and if the carriage 2 was moved to the right in the printing pass process (S106: YES), the control device 80 causes the carriage 2 to face the cap. position (S107), and if the carriage 2 has moved to the left in the printing pass process (S106: NO), the carriage 2 is moved to the form facing position (S108). As a result, the carriage 2 is moved from the position when the printing pass process is completed to the closer position between the cap facing position and the form facing position. In S107 and S108, the carriage 2 is moved so that it reaches the cap facing position or the form facing position by a predetermined timing which will be described later.

When the carriage 2 is moved to the cap facing position in S107, the control device 80 subsequently causes the laser irradiation unit 66 to irradiate the laser beam L1 at a predetermined timing described later (S109). It is determined whether or not the light quantity of the laser light L1 received by the laser light receiving section 67 is equal to or greater than a predetermined light quantity (S110).

Here, for the nozzles 10 that are normally ejecting ink at present but are likely to stop ejecting ink in the near future, after the ink is ejected, the vibration of the meniscus of the ink in the nozzle 10 is sufficiently attenuated. During this time, ink may overflow from the nozzle 10 to the nozzle surface 4a as indicated by symbol A in FIGS. 4(a) and 4(b). When the overflow occurs, part of the laser light L1 emitted from the laser irradiation unit 66 in S109 is blocked by the overflowed ink, and compared to the case where the overflow does not occur, The amount of laser light L1 received by the laser light receiving portion 67 is reduced. Therefore, in the first embodiment, in S110, it is determined whether or not the overflow occurs depending on whether or not the light amount of the laser light L1 received by the laser light receiving section 67 is equal to or greater than a predetermined light amount. The same applies to the determination in S114, which will be described later.

If it is determined that the amount of laser light L1 received by the laser light receiving unit 67 is equal to or greater than the predetermined amount and that the above overflow has not occurred (S110: YES), the control device 80 moves the carriage 2 to the cap facing position. , the inkjet head 4 is controlled to perform flushing toward the cap 61 (S111), and the process proceeds to S117. If it is determined that the amount of laser light L1 received by the laser light receiving unit 67 is less than the predetermined amount and that the overflow occurs (S110: NO), the controller 80 moves the carriage 2 to the cap facing position. , the above-described suction purge is performed (S112), and the process proceeds to S117.

When the carriage 2 is moved to the position facing the form in S108, the control device 80 subsequently causes the laser irradiation unit 68 to irradiate the laser beam L2 at a predetermined timing described later (S113). It is determined whether or not the light quantity of the laser light L2 received by the laser light receiving portion 69 is equal to or greater than a predetermined light quantity (S114).

When it is determined that the light amount of the laser light L2 received by the laser light receiving unit 69 is equal to or greater than the predetermined light amount and that the above-mentioned overflow does not occur (S114: YES), the control device 80 moves the carriage 2 to the form facing position. , the inkjet head 4 is controlled to perform flushing toward the flushing foam 9 (S111), and the process proceeds to S117. When it is determined that the amount of laser light L2 received by the laser light receiving unit 69 is less than the predetermined amount and that the overflow occurs (S114: NO), the controller 80 controls the carriage motor 86. After moving the carriage 2 to the position facing the cap (S115), the suction purge described above is performed (S116), and the process proceeds to S117.

In S117, the value of variable M is reset to 0. Subsequently, when recording on the recording paper P is not completed (S118: NO), the control device 80 controls the transport motor 87 to cause the transport rollers 6 and 7 to transport the recording paper P by a predetermined distance. After carrying out the transport operation (S119), the process returns to S103.

When the recording on the recording paper P is completed (S118: YES), the control device 80 controls the transport motor 87 to cause the transport rollers 6 and 7 to discharge the recording paper P from the printer 1. A paper ejection operation is performed (S120), and the process ends.

<Predetermined timing>
Next, the predetermined timing for performing the irradiation of the laser beams L1 and L2 in S109 and S113 and the determination based on the light quantity of the received laser beams L1 and L2 in S110 and S114 will be described. In the printer 1, in the printing pass process of S103, under the control of the control device 80, as shown in FIG. The drive element 50 of the inkjet head 4 is driven. At this time, among these plurality of drive signals, the last output drive signal starts to be output at time _Tk , and at time _Ek after that (“final ejection time point” in the present invention), Ink is ejected from the nozzle 10 .

Further, after pressure is applied to the ink in the pressure chamber 40 and the ink is ejected from the nozzle 10, the meniscus of the ink in the nozzle 10 vibrates in the vertical direction at a period of 2×AL. More specifically, as shown in FIG. 8B, at the time when the ink is ejected from the nozzle 10, the displacement of the ink in the nozzle 10 toward the lower side of the meniscus becomes maximum. oscillates in the vertical direction at a period of 2×AL while damping. Here, AL is the time required for the pressure wave generated in the pressure chamber 40 by driving the drive element 50 to propagate to the connecting portion between the individual channel 46 and the manifold channel 41 .

Further, such meniscus vibration is normally generated for a period of time twice the drive period U after the certain drive signal from the point of time when ink is ejected from the nozzle 10 by a certain drive signal. A certain amount of time remains until the elapse of .

Further, as shown in FIG. 8B, the period between the time E _k and the time when 0.5×AL has passed from the time E _k , and N is an integer of 0 or more, and from the time E _k to [ (1.5+2×N)×AL] and [(2.5+2×N)×AL] after time E _k , the meniscus of the ink in the nozzle 10 vibrates. It is displaced to the lower side than when it is not. Therefore, the overflow is particularly large during these periods, and if the predetermined timing is the timing within these periods, the laser beam received by the laser light receiving units 67 and 69 depends on whether or not the overflow occurs. The difference in the amount of light can be increased.

On the other hand, since the oscillation of the meniscus is attenuated with the lapse of time, the overflow increases in earlier periods among these periods. However, if the timing within the period between time _Ek , which is the earliest period among these periods, and the time point after 0.5×AL has passed from time _Ek , is the predetermined timing, laser light L1, L2 may be blocked by ink ejected from nozzle 10 .

Therefore, in the first embodiment, the predetermined timing is the period between the point in time when 1.5×AL has passed from the time E _k and the point in time when 2.5×AL has passed from the time E _k when N=0. The timing is within Ra. This timing is the point in time when twice the drive period U has elapsed after the drive period for outputting the last drive signal (the drive period from time T _k to time T _k+1 ) from time E _k ( It is also the timing within the determination period Rb up to time T _k+3 ).

Further, the predetermined timing is individually determined for each nozzle row 19 based on the final ejection timing in the printing pass process. If the predetermined timing differs between the nozzle rows 19, in S107 and S108, the carriage 2 is moved to the cap facing position or the form facing position by the earliest predetermined timing. The same applies to the third to be described later.

In S109 and S113, laser light is emitted from the corresponding laser irradiation units 66 and 68 at a predetermined timing for each nozzle row 19 . In S110 and S114, one of the plurality of nozzles 10 forming the nozzle row 19 is detected based on the amount of laser light received by the corresponding laser light receiving units 67 and 69 at a predetermined timing for each nozzle row 19. , it is determined whether or not the overflow occurs. The same applies to second to fifth embodiments, which will be described later.

<effect>
In the first embodiment, laser light is received from the laser irradiation units 66 and 68 at a predetermined timing within the determination period Rb in which the meniscus of the ink in the nozzle 10 remains vibrating to some extent due to the ejection of ink by the last drive signal. By irradiating the laser beam toward the portions 67 and 69 so as to pass over the nozzle surface 4a, it is possible to determine whether or not the overflow occurs. Depending on whether or not the overflow occurs, it is possible to detect in advance the nozzles 10 that are highly likely to stop ejecting ink in the near future.

Further, in the first embodiment, as described above, in the determination period, the period between the time E _k and the time point after 0.5×AL has passed from the time E _k , and N is an integer of 0 or more As a result _, the _overflow becomes particularly large. Therefore, in the first embodiment, one of these periods, which is a time point after [(1.5+2×N)×AL] has passed from time E _k and a time point after time E _k has passed [(2.5+2×N )×AL] is set as the predetermined timing. This makes it possible to increase the difference in the amount of laser light received by the laser light receiving portions 67 and 69 depending on whether or not the overflow occurs.

Further, in the first embodiment, it is determined whether or not the above-mentioned overflow has occurred by using ejection of ink from the nozzles 10 toward the recording paper P in the recording pass process. Therefore, it is not necessary to separately eject ink from the nozzles 10 for this determination.

In addition, in the first embodiment, when there is a nozzle 10 that is highly likely to stop ejecting ink in the near future due to the above-mentioned overflow, ink is discharged from the nozzle 10 by suction purge. It is possible to prevent the ink from being discharged from the nozzle.

Further, in the first embodiment, after the printing pass process, it is determined whether or not the overflow occurs when the variable M is equal to or greater than the predetermined value Ma and the flushing should be performed. Flushing is performed when it is determined that the overflow has not occurred, and purging is performed instead of flushing when it is determined that the overflow has occurred. As a result, it is possible to prevent the ink from being ejected from the nozzles 10 that are highly likely to stop ejecting ink in the near future, and to prevent the other nozzles 10 from drying out.

Also, in the first embodiment, the determination period Rb described above is not so long. Therefore, in the first embodiment, the cap 61 is provided with a laser irradiation portion 66 and a laser light receiving portion 67, and the flushing foam 9 is provided with a laser irradiation portion 68 and a laser light receiving portion 69. FIG. Then, after the printing pass process, if the variable M is equal to or greater than a predetermined value Ma, it is moved to the closer position between the cap facing position and the form facing position. As a result, it is possible to immediately determine whether or not the overflow occurs after the printing pass process.

Further, in the first embodiment, when the carriage 2 is moved to the cap facing position and it is determined based on the amount of laser light received by the laser light receiving section 67 that the overflow has occurred, the carriage 2 Suction purge is performed while the is positioned opposite to the cap.

Further, in the first embodiment, when the carriage 2 is moved to the position facing the form and it is determined based on the amount of laser light received by the laser light receiving section 69 that the overflow has occurred, the carriage 2 is moved to the position facing the cap, and then suction purge is performed.

Further, in the first embodiment, when the carriage 2 is moved to the cap facing position and it is determined based on the amount of laser light received by the laser light receiving section 67 that the overflow has not occurred, the carriage 2 is located at the cap facing position, flushing is performed. When the carriage 2 is moved to the position facing the form and it is determined based on the amount of laser light received by the laser light receiving section 69 that the overflow does not occur, the carriage 2 is positioned at the position facing the form. Suction purge is performed with the This eliminates the need to move the carriage 2 for flushing.

[Second embodiment]
Next, a preferred second embodiment of the invention will be described. The second embodiment, like the first embodiment, relates to the printer 1, but the second embodiment differs from the first embodiment in control during printing.

In the second embodiment, the control device 80 performs processing along the flow of FIG. 9 when a recording command is input. More specifically, when a recording command is input, the control device 80 executes the same processes as S101 to S108, as in the first embodiment.

Then, when the carriage 2 is moved to the cap facing position in S107, the controller 80 causes the laser irradiation unit 66 to irradiate laser light (S201), and controls the inkjet head 4. , to the cap 61 ("first flushing" of the present invention) (S202). In S202, the control device 80 controls the driver IC 59 to output a plurality of drive signals to the ink jet head 4 at the drive cycle U to perform flushing.

Subsequently, the control device 80 determines whether or not the amount of laser light received by the laser light receiving section 67 at a predetermined timing is equal to or greater than a predetermined amount (S203). The predetermined timings in the second embodiment are the point in time when 1.5×AL has passed since the final ejection time, which is the point at which the last ink is ejected in the flushing in S203, and the point in time when 2.5×AL has passed since the final ejection time. It is the timing within the period between This timing is the timing within the period (“determination period” of the present invention) from the time of the final ejection to the time when twice the time of the drive cycle U has elapsed after the drive cycle for outputting the last drive signal. But also.

When it is determined that the amount of laser light received by the laser light receiving unit 67 is equal to or greater than the predetermined amount of light and that the overflow does not occur (S203: YES), the value of the variable M is reset to 0 (S205). ), and proceeds to S118 as in the first embodiment. If it is determined that the amount of laser light received by the laser light receiving unit 67 is less than the predetermined amount and that the overflow occurs (S203: NO), the control device 80 moves the carriage 2 to the position facing the cap. After the suction purge is performed while it is positioned (S204), the value of the variable M is reset to 0 (S205), and the process proceeds to S118. The processing after S118 is the same as in the first embodiment.

When the carriage 2 is moved to the position facing the form in S108, the controller 80 causes the laser irradiation unit 68 to irradiate laser light (S206), and controls the inkjet head 4 to perform flushing. A flushing (“second flushing” of the present invention) is performed toward the form 9 (S207). In S207, similarly to S202, under the control of the control device 80, the driver IC 59 outputs a plurality of driving signals to the inkjet head 4 in the driving period U to perform flushing.

Subsequently, the control device 80 determines whether or not the amount of laser light received by the laser light receiving section 69 at the predetermined timing is equal to or greater than a predetermined amount (S208). When it is determined that the amount of laser light received by the laser light receiving unit 69 is equal to or greater than the predetermined amount of light and the overflow does not occur (S208: YES), the value of the variable M is reset to 0 ( S205) and proceed to S118. When it is determined that the amount of laser light received by the laser light receiving unit 69 is less than the predetermined amount and that the overflow occurs (S208: NO), the control device 80 controls the carriage motor 86. After the carriage 2 is moved to the cap facing position (S209), suction purge is performed (S204), the value of the variable M is reset to 0 (S205), and the process proceeds to S118.

<effect>
In the second embodiment, ejection of ink from the nozzles 10 during flushing is used to determine whether or not the overflow occurs. Therefore, it is not necessary to separately eject ink from the nozzles 10 for this determination.

Furthermore, in the second embodiment, after the printing pass process, when the variable M is equal to or greater than the predetermined value Ma, the carriage is moved to the closer position between the cap facing position and the form facing position, and flushing is performed at that position. Then, it is determined whether or not the overflow occurs. As a result, it is possible to shorten the moving distance of the carriage 2 for determining whether or not the overflow occurs after the printing pass.

Further, in the second embodiment, when the carriage 2 is moved to the cap facing position and it is determined based on the amount of laser light received by the laser light receiving section 67 that the overflow has occurred, the carriage 2 Suction purge is performed while the is positioned opposite to the cap.

Further, in the second embodiment, when the carriage 2 is moved to the position facing the form and it is determined based on the amount of laser light received by the laser light receiving section 69 that the overflow has occurred, the carriage 2 is moved to the position facing the cap, and then suction purge is performed.

[Third embodiment]
Next, a preferred third embodiment of the invention will be described. As shown in FIG. 10, the printer 100 according to the third embodiment is the same as the printers 1 according to the first and second embodiments except that the flushing foam 9, the laser irradiation section 68 and the laser light receiving section 69 are removed.

In the third embodiment, the control device 80 performs processing according to the flow of FIG. 11 when a recording command is input. More specifically, when a recording command is input, the control device 80 executes the same processes as S101 to S105, as in the first embodiment. Then, when the variable M is less than the predetermined value Ma (S105: NO), the process proceeds to S118 as in the first embodiment. When the variable M is greater than or equal to the predetermined value Ma (S105: YES), the control device 80 executes the processes of S107, S109 to S112, S117 described in the first embodiment, and then proceeds to S118. The processing after S118 is the same as in the first embodiment.

<effect>
In the third embodiment, similarly to the first embodiment, the discharge of ink from the nozzles 10 toward the recording paper P in the recording pass process is used to determine whether or not the above overflow has occurred. Therefore, it is not necessary to separately eject ink from the nozzles 10 for this determination.

Further, in the third embodiment, as in the first embodiment, ink is prevented from being ejected from the nozzles 10 by discharging the ink from the nozzles 10 by suction purge when the overflow occurs. be able to.

Also in the third embodiment, as in the first embodiment, it is determined whether or not the overflow occurs when the variable M is equal to or greater than the predetermined value Ma after the printing pass process and the flushing should be performed. . Flushing is performed when it is determined that the overflow has not occurred, and purging is performed instead of flushing when it is determined that the overflow has occurred. As a result, it is possible to prevent the ink from being ejected from the nozzles 10 that are highly likely to stop ejecting ink in the near future, and to prevent the other nozzles 10 from drying out.

[Fourth embodiment]
Next, a preferred fourth embodiment of the invention will be described. Like the third embodiment, the fourth embodiment relates to the printer 100, but the fourth embodiment differs from the third embodiment in control during printing.

In the fourth embodiment, the control device 80 performs processing according to the flow of FIG. 12 when a recording command is input. More specifically, when a recording command is input, the control device 80 executes the same processes as S101 to S105, as in the third embodiment. Then, when the variable M is less than the predetermined value Ma (S105: NO), the process proceeds to S118. When the variable M is greater than or equal to the predetermined value Ma (S105: YES), the control device 80 performs the same processes of S107 and S201 to S205 as in the second embodiment, and then proceeds to S118. The processing after S118 is the same as in the first embodiment.

<effect>
In the fourth embodiment, it is determined whether or not the above-mentioned overflow has occurred by utilizing the ejection of ink from the nozzles 10 during flushing. There is no

In addition, in the fourth embodiment, when there is a nozzle 10 that is highly likely to stop ejecting ink in the near future due to the above-mentioned overflow, ink is discharged from the nozzle 10 by suction purge. It is possible to prevent the ink from being discharged from the nozzle.

Further, in the fourth embodiment, flushing is performed by ejecting ink from the nozzle 10 toward the cap 61 serving as a liquid receiver (the cap 61 also serves as a liquid receiver), so it is determined that the overflow occurs. , the suction purge can be performed without moving the carriage 2.

[Fifth embodiment]
Next, a preferred fifth embodiment of the present invention will be described. As shown in FIG. 13, in the printer 120 according to the fifth embodiment, in the printer 1 according to the first embodiment, the cap 61 is located on the right side in the scanning direction, and the flushing foam 9 is located on the platen 5 in the scanning direction. and the cap 61 . That is, in the fifth embodiment, the cap 61 and the flushing foam 9 are arranged on the same side with respect to the platen 5 (ejection range in the printing pass process) in the scanning direction. Further, in the fifth embodiment, as in the first embodiment, the flushing foam 9 is provided with four laser irradiation units 68 and four laser light receiving units 69. However, unlike the first embodiment, the cap 61 is not provided with a laser irradiation section and a laser light receiving section.

In the fifth embodiment, the control device 80 performs processing along the flow of FIG. 14 when a recording command is input. More specifically, when a recording command is input, the control device 80 executes the same processes as S101 to S105, as in the first embodiment. Then, when the variable M is less than the predetermined value Ma (S105: NO), the process proceeds to S118. The processing after S118 is the same as in the first embodiment.

When the variable M is equal to or greater than the predetermined value Ma (S105: YES), the controller 80 controls the carriage motor 86 to move the carriage 2 to the position facing the form (S108), and similarly to the second embodiment, the laser irradiation unit 68 is irradiated with laser light (S206), and the inkjet head 4 is controlled to perform flushing (S207). Then, it is determined whether or not the amount of laser light received by the laser light receiving unit 69 at the predetermined timing similar to the second embodiment is equal to or greater than the predetermined amount (S208).

When it is determined that the light amount of the laser light received by the laser light receiving unit 69 at the predetermined timing is equal to or greater than the predetermined light amount and the overflow does not occur (S208: YES), the control device 80 The value is reset to 0 (S117), and the process proceeds to S118.

If it is determined that the amount of laser light received by the laser light receiving unit 69 at the predetermined timing is less than the predetermined amount and that the overflow has occurred (S208: NO), the controller 80 controls the carriage motor 86 is controlled to move the carriage 2 to the cap facing position (S301), and then the suction purge is performed (S302). Then, the value of the variable M is reset to 0 (S117), and the process proceeds to S118.

<effect>
In the fifth embodiment, ejection of ink from the nozzles 10 during flushing is used to determine whether or not the above overflow has occurred. Therefore, ink is ejected from the nozzles 10 separately for this determination. No need.

In addition, in the fifth embodiment, when there is a nozzle 10 that is likely to stop ejecting ink in the near future due to the above overflow, ink is discharged from the nozzle 10 by suction purging. It is possible to prevent the ink from being discharged from the nozzle.

Further, in the fifth embodiment, the cap 61 and the flushing foam 9 are arranged on the same side with respect to the platen 5 in the scanning direction. As a result, when it is determined that the overflow has occurred, it is possible to shorten the movement distance when moving the carriage 2 from the form facing position to the cap facing position in order to perform the suction purge.

[Sixth embodiment]
Next, a preferred sixth embodiment of the present invention will be described. As shown in FIGS. 15 and 16, a printer 140 according to the sixth embodiment includes a head bar 141, a platen 142, transport rollers 143 and 144 (a "transport unit" of the present invention), and a flushing foam 145. I have.

The head bar 141 includes four inkjet heads 151 , a support member 152 , eight laser irradiation units 153 and eight laser light reception units 154 . The four inkjet heads 151 eject ink from a plurality of nozzles 150 formed on a nozzle surface 151a, which is the lower surface thereof. More specifically, the nozzle surface 151a is a surface parallel to the mutually orthogonal scanning direction (“first direction” of the present invention) and transport direction (“second direction” of the present invention). That is, the scanning direction and the transport direction are directions along the nozzle surface 151a. The plurality of nozzles 150 are arranged in the scanning direction to form nozzle rows 149, and four nozzle rows 149 are arranged in the transport direction on the nozzle surface 151a. Then, black, yellow, cyan, and magenta inks are ejected from the plurality of nozzles 150 , starting from those that constitute the nozzle row 149 on the upstream side in the transport direction.

In addition, the inkjet head 151, like the inkjet head 4 of the first embodiment, includes a plurality of individual channels each including a nozzle 150 and a pressure chamber (not shown), a manifold channel (not shown) communicating with the plurality of individual channels, A plurality of individual driving elements 155 (see FIG. 17) are provided for a plurality of nozzles 150 (pressure chambers). By driving the drive element 155 , pressure is applied to the ink in the pressure chamber, thereby ejecting the ink from the plurality of nozzles 150 .

Also, two of each of the four inkjet heads 151 are arranged at intervals in the scanning direction. Also, among the four inkjet heads 151, the two inkjet heads 151 aligned in the scanning direction and the remaining two inkjet heads 151 aligned in the scanning direction are arranged shifted in the scanning direction and the transport direction. Thereby, the plurality of nozzles 150 of the four inkjet heads 151 are arranged over the entire length of the recording paper P in the scanning direction.

The support member 152 is a substantially rectangular plate-shaped member whose longitudinal direction is the scanning direction. there is The eight laser irradiation units 153 are arranged at the left end of the support member 152 and arranged in the transport direction. Of the eight laser irradiation units 153, the four laser irradiation units 153 on the upstream side in the transport direction are aligned with the four nozzle rows 149 of the two inkjet heads 151 arranged on the upstream side in the transport direction. are the same. Of the eight laser irradiation units 153, the four laser irradiation units 153 on the downstream side in the transport direction are aligned with the four nozzle rows 149 of the two inkjet heads 151 arranged on the downstream side in the transport direction. are the same.

The eight laser light receivers 154 are arranged at the left end of the support member 152 and arranged in the transport direction. The eight laser light receiving units 154 correspond to the eight laser irradiation units 153, and the positions in the conveying direction are the same as the corresponding laser irradiation units 154. As shown in FIG. Accordingly, the laser light receiving section 154 is arranged on the opposite side of the inkjet head 151 from the laser irradiation section 153 in the scanning direction.

In addition, each laser irradiation section 153 and each laser light receiving section 154 have the same vertical position as the nozzle surface 151a. Each laser irradiation unit 153 irradiates the laser light L3 in the scanning direction toward the corresponding laser light receiving unit 154 . As a result, the laser light L3 passes through the portions where the corresponding nozzle rows 149 are arranged on the nozzle surfaces 151a of the two inkjet heads 151 arranged in the transport direction.

The platen 142 is arranged below the head bar 141 and faces the plurality of nozzles 150 of the four inkjet heads 151 . The platen 142 supports the recording paper P from below. The transport roller 143 is arranged upstream of the platen 142 in the transport direction. The transport roller 144 is arranged downstream of the platen 142 in the transport direction. The transport rollers 143 and 144 are connected to a transport motor 161 (see FIG. 17) via gears (not shown). direction.

The flushing foam 145 is positioned between the head bar 141 and the platen 142 in the vertical direction. Also, the flushing foam 145 can be moved in the scanning direction by an ink receiver switching section 162 (see FIG. 17, "liquid receiver switching section" of the present invention). As a result, in the printer 140, the flushing foam 145 is arranged in a non-opposing position that does not face the four inkjet heads 151, on the right side of the head bar 141 and the platen 142 in the scanning direction, as indicated by solid lines in FIG. the “second state” of the present invention), and the state in which the flushing foam 145 is arranged at a position facing the four inkjet heads 151 (the “first state” of the present invention), which is indicated by a chain double-dashed line in FIG. 15 . can be switched.

Next, the electrical configuration of printer 140 will be described. The operation of printer 140 is controlled by controller 160 . As with the control device 80, the control device 160 includes a CPU 81, a ROM 82, a RAM 83, a flash memory 84, an ASIC 85, and the like. The control device 160 controls the operations of the transport motor 161, the laser irradiation section 153, the ink receiving switching section 162, and the like. The control device 160 also controls the driving elements 155 of the four inkjet heads 151 by controlling the driver ICs 159 connected to the driving elements 155 . However, hereinafter, for the sake of simplification of description, it may be said that "the control device 160 controls the inkjet head 151" or the like. A signal corresponding to the amount of received laser light is input to the control device 160 from the laser light receiving section 154 .

<Control during recording>
Next, the control of the control device 160 when recording on the recording paper P in the printer 140 will be described. In the printer 140, the controller 160 performs processing according to the flow of FIG. 18 when a print command is input.

More specifically, when a recording command is input, the control device 160 controls the conveying motor 161 to cause the conveying rollers 143 and 144 to convey the recording paper P in the conveying direction. to perform a recording operation (“ejection operation” of the present invention), which is an operation of ejecting ink from a plurality of nozzles 150 toward the recording paper P (S401). Also in S401, as described in the first embodiment, the driver IC 159 outputs a plurality of driving signals to the inkjet head 151 at a predetermined driving cycle U under the control of the control device 160, thereby driving the plurality of nozzles 150. Ink is ejected from the Further, when recording on the recording paper P is being performed, the flushing foam 145 is positioned at the non-facing position (in the second state).

After completing the recording operation, the control device 160 waits until a predetermined timing (S402: NO). Here, the predetermined timing in the sixth embodiment is the point of time when 1.5×AL has passed since the final ejection time, which is the point of time when ink is ejected by the last drive signal in the printing operation, and the point of time when 2.5×AL has passed since the final ejection time. It is the timing within the period between the elapsed time points. Further, in the sixth embodiment, the predetermined timing is determined for each two nozzle rows 149 corresponding to each laser irradiation section 153 and laser light receiving section 154 .

Then, when the predetermined timing comes (S402: YES), the control device 160 causes the laser irradiation unit 153 to irradiate the laser beam (S403). When it is determined that there is no overflow (S404: YES), the process is terminated.

If it is determined that the amount of laser light received by the laser light receiving section 154 is less than the predetermined amount and that the above-described overflow has occurred (S404: NO), the control device 160 then switches to the ink receiver switching section. 162 to move the flushing foam 145 to the opposing position (switch to the first state) (S405), and then control the inkjet head 151 to perform flushing toward the flushing foam 145 (S406). . After completion of the flushing, the controller 160 controls the ink receiver switching unit 162 to return the flushing foam 145 to the non-facing position (S407), and the process ends.

<effect>
In the sixth embodiment, similarly to the first embodiment, the overflow may occur during the determination period in the nozzles 150 that are highly likely to stop ejecting ink in the near future. Therefore, in the sixth embodiment, it is determined whether or not the overflow occurs based on the amount of laser light received by the laser light receiving section 154 at a predetermined timing within the determination period. This makes it possible to detect in advance the nozzles 150 that are highly likely to stop ejecting ink in the near future. In addition, in the sixth embodiment, since the support member 152 that supports the inkjet head 151 is provided with the laser irradiation unit 153 and the laser light receiving unit 154, it is possible to quickly check whether or not the overflow occurs when necessary. can judge.

In addition, in the sixth embodiment, two inkjet heads 151 arranged in the scanning direction are arranged between a pair of laser irradiation section 153 and laser light receiving section 154 . Therefore, it is possible to determine whether or not the above overflow occurs for these two inkjet heads 151 using a set of the laser irradiation unit 153 and the laser light receiving unit 154 .

Further, in the sixth embodiment, ejection of ink from the nozzles 150 toward the recording paper P during recording on the recording paper P is used to determine whether or not the above-described overflow has occurred. Therefore, it is not necessary to separately eject ink from the nozzles 150 for this determination.

Further, in the sixth embodiment, when recording on the recording paper P, the flushing foam 145 is positioned at a non-facing position so that the flushing foam 145 does not interfere with recording on the recording paper P. On the other hand, when overflow occurs, flushing can be performed from the nozzle 150 toward the flushing foam 145 by moving the flushing foam 145 to the opposing position.

<Modification>
Although the preferred first to sixth embodiments of the present invention have been described above, the present invention is not limited to the first to sixth embodiments, and various modifications are possible within the scope of the claims. is.

In the first embodiment, when the carriage 2 is moved to the cap-facing position after the printing pass process, and when it is determined that the overflow occurs, the carriage 2 remains positioned at the cap-facing position. Although the flushing is performed toward the cap 61, it is not limited to this. For example, in the above case, the carriage 2 may be moved from the cap facing position to the foam facing position to perform flushing toward the flushing foam 9 .

Further, in the first embodiment, the cap 61 is provided with the laser irradiation portion 66 and the laser light receiving portion 67, and the flushing foam 9 is provided with the laser irradiation portion 68 and the laser light receiving portion 69, but the present invention is not limited to this. . For example, in Modified Example 1, as shown in FIG. 19, in the printer 170, between the platen 5 (maximum ejection range in the printing pass process) and the cap 61 in the scanning direction, the laser irradiation unit 66 and the laser light receiving unit 67 is provided, and a laser irradiation section 68 and a laser light receiving section 69 are provided between the platen 5 and the flushing foam 9 .

In this case, when the carriage 2 is moved to the cap facing position or the form facing position in S107 and S108, the carriage 2 is moved to the laser irradiation portion 66 and the laser light receiving portion 67 corresponding to the nozzle row 19 at the predetermined timing described above. or a position between the laser irradiation unit 68 and the laser light receiving unit 69 to which the nozzle row 19 corresponds. Then, the irradiation of the laser light in S107 or S113 is performed at the predetermined timing described above.

Further, in Modification 1, when the predetermined timings are different between the nozzle rows 19, in S107 and S108, the carriage 2 is moved to the laser irradiation unit 66 and the laser light receiving unit corresponding to the nozzle rows 19 by the earliest predetermined timing. 67, or to a position where the nozzle row 19 is between the corresponding laser irradiation unit 68 and laser light receiving unit 69, and the carriage 2 is temporarily stopped. Then, the laser light irradiation of S109 or S113 is performed at a predetermined timing for each nozzle row 19 . After that, the carriage 2 is moved to the cap facing position or the form facing position.

In Modification 1, the position of the carriage 2 when the nozzle row 19 is positioned between the corresponding laser irradiation portion 66 and the laser light receiving portion 67, and the laser irradiation portion 68 and the laser light receiving portion to which the nozzle row 19 corresponds. The position of the carriage 2 when positioned between the portion 69 and the portion 69 respectively correspond to the "determination position" of the present invention.

In addition, in the second embodiment, the suction purge is performed when it is determined that the overflow occurs, but the present invention is not limited to this. For example, flushing may be further performed when it is determined that the overflow occurs.

Also, in the fourth embodiment, the cap 61 also serves as a liquid receiver, but the present invention is not limited to this. For example, in the fourth embodiment, the flushing foam 9, the laser irradiation section 68 and the laser light receiving section 69 may be provided, and the cap 61 may not be provided with the laser irradiation section and the laser light receiving section. In this case, the carriage 2 is moved to the position facing the form to perform flushing, and it is determined whether or not the overflow occurs. Then, when it is determined that the above-mentioned overflow has occurred, the carriage 2 is moved to the position facing the cap, and the suction purge is performed.

Moreover, in the fifth embodiment, the cap 61 and the flushing foam 9 are arranged on the same side with respect to the platen 5 in the scanning direction, but this is not the only option. For example, in the fifth embodiment, the cap 61 and the flushing foam 9 may be arranged on opposite sides of the platen 5 in the scanning direction, as in the first embodiment.

Further, in the first to fifth embodiments, the flushing condition for performing flushing is that the value of the variable M is equal to or greater than the predetermined value Ma, but the present invention is not limited to this. The flushing condition may be another condition such as, for example, a condition on the elapsed time since the last flushing or since the last suction purge.

In addition, in the first and third embodiments, it is determined whether or not the overflow occurs when the flushing condition is satisfied after the printing pass, but the present invention is not limited to this. It may be determined whether or not the overflow occurs at a timing other than when the flushing condition is satisfied, and the suction purge may be performed when it is determined that the overflow occurs.

In the first and third embodiments, suction purge is performed when it is determined that the overflow occurs, and flushing is performed when it is determined that the overflow does not occur. is not limited. For example, flushing is performed regardless of whether or not the overflow has occurred, and when it is determined that the overflow has occurred, the flushing is more likely than when it is determined that the overflow has not occurred. For example, the amount of discharged ink may be increased.

In addition, in the sixth embodiment, the flushing foam 145 is movable between the facing position facing the four inkjet heads 151 and the non-facing position not facing the four inkjet heads 151. is not limited. For example, the flushing foam 145 is fixed at the position indicated by the solid line in FIG. 15, and the head bar 141 is movable in the scanning direction between a position facing the platen 142 and a position facing the flushing foam 145. and the ink receiver switching unit 162 may move the head bar 141 between the two positions. In this case, the state in which the head bar 141 faces the platen 142 corresponds to the "first state" of the present invention, and the state in which the head bar 141 faces the flushing foam 145 corresponds to This corresponds to the "second state" of the present invention.

Further, in Modification 2, as shown in FIGS. 20A and 20B, through holes 182 are formed through the platen 181 in the vertical direction. Further, the platen 181 is provided with an opening/closing portion 183 for opening and closing the through-hole 182 by swinging around a swing shaft 183a parallel to the scanning direction (the direction perpendicular to the paper surface of FIGS. 20(a) and (b)). It is Also, the flushing foam 145 is arranged at a position overlapping the platen 181 in the vertical direction, and can be moved up and down between a lower position below the platen 181 and an upper position above the platen 181 . The ink receiver switching unit 162 swings the open/close unit 183 to open and close the through hole 182 and raise and lower the platen 181 between the lower position and the upper position.

In the modified example 2, when recording on the recording paper P, as shown in FIG. . When performing flushing, as shown in FIG. 20(b), the opening/closing portion 183 is swung to open the through hole 182, and then the flushing foam 145 is moved to the upper position. In Modification 2, the state of FIG. 20(a) corresponds to the "second state" of the present invention, and the state of FIG. 20(b) corresponds to the "first state" of the present invention.

21(a) and 21(b), a flushing foam 191 extending obliquely with respect to the conveying direction and the vertical direction is provided upstream and above the platen 142 in the conveying direction. are placed. Further, the support member 192 is capable of swinging around a swing shaft 192a parallel to the scanning direction (the direction perpendicular to the paper surface of FIGS. 21(a) and 21(b)). Then, the ink receiving switching unit 162 swings the support member 192 to move the head bar 190 to the recording position shown in FIG. b), the plurality of inkjet heads 151 are moved between flushing positions facing the flushing foam 191; In Modification 3, the state of FIG. 21(a) corresponds to the "second state" of the present invention, and the state of FIG. 21(b) corresponds to the "first state" of the present invention.

In this case, by recording on the recording paper P with the head bar 190 positioned at the recording position shown in FIG. never Also, by positioning the head bar 190 at the flushing position shown in FIG.

Furthermore, in the sixth embodiment, the first state in which the ink ejected from the four inkjet heads 151 nozzles 150 is received by the flushing foam, and the ink ejected from the four inkjet heads 151 nozzles 150 are received by the flushing foam. It is not limited to switching between the second state and the non-existing second state. For example, there may be no flushing foam and the flushing may be directed toward the platen.

Further, in the sixth embodiment, an example in which the support member 152 of the head bar 141 having the plurality of inkjet heads 151 is provided with the laser irradiation unit 153 and the laser light receiving unit 154 has been described, but the present invention is not limited to this. For example, in a so-called serial printer as described in the first to fifth embodiments, the carriage 2 (the “supporting member” of the present invention) may be provided with a laser irradiation section and a laser light receiving section.

In addition, in the sixth embodiment, it is determined whether or not the overflow occurs by using the ejection of ink from the nozzles 150 during recording on the recording paper P, but the present invention is not limited to this. For example, flushing may be performed separately from ejection of ink onto the recording paper P, and the ejection of ink from the nozzles 150 during this flushing may be used to determine whether or not the above overflow has occurred.

In the above example, the point of time 1.5×AL has elapsed from the final ejection point, which is the point of time of ejection of ink by the last drive signal in printing on the recording paper P or flushing, and the point of time 2.5×AL has elapsed from the final ejection point. Although the timing within the period between the time when AL has passed is used as the predetermined timing to determine whether or not the above-described overflow has occurred, the timing is not limited to this. For example, it may be determined whether or not the overflow occurs by using the timing within the period between the time of the final ejection and the time when 0.5×AL has passed from the time of the final ejection as the predetermined timing.

Alternatively, where N is an integer equal to or greater than 1, the time point after [(1.5+2×N)×AL] has passed since the final ejection time and the time point after [(2.5+2×N)×AL] has passed since the final ejection time. It may be determined whether or not the overflow occurs by using the timing within the interval as the predetermined timing. However, in this case, it is necessary to set the integer N such that the period falls within the above-described determination period.

Further, after the drive cycle for outputting the last drive signal from the final ejection time, which is the time of ejection of the ink by the last drive signal in printing on the recording paper P or flushing, the time is double the drive cycle. It may be determined whether or not the overflow occurs by using a timing other than the timing described above within the determination period up to the elapsed time as a predetermined timing.

In the above description, an example in which the present invention is applied to a printer that records on the recording paper P by ejecting ink from nozzles has been described, but the present invention is not limited to this. The present invention can also be applied to image recording apparatuses that record images on recording media other than recording paper, such as T-shirts, outdoor advertising sheets, mobile terminal cases such as smartphones, cardboard, and resin members. Further, the present invention can also be applied to a liquid ejecting apparatus that ejects liquid other than ink, such as liquid resin or metal.

REFERENCE SIGNS LIST 1 printer 2 carriage 4 inkjet head 4a nozzle surface 9 flushing foam 10 nozzle 40 pressure chamber 41 manifold channel 46 individual channel 50 drive element 61 cap 62 suction pump 66, 68 laser irradiation unit 67, 69 laser light receiving unit 80 control device 86 Cap lifting mechanism 100 Printer 120 Printer 140 Printer 143, 144 Conveying roller 145 Flushing foam 150 Nozzle 151 Ink jet head 151a Nozzle surface 152 Supporting member 153 Laser irradiation unit 154 Laser light receiving unit 160 Control unit 161 Conveying motor 162 Ink receiver switching unit 170 Printer 183 Opening/closing portion 191 Flushing foam 192 Supporting member

Claims (21)

a liquid ejection head having nozzles and a nozzle surface on which the nozzles are formed;
a laser irradiation unit that irradiates laser light in a first direction along the nozzle surface;
a laser light receiving unit arranged in the first direction with a gap from the laser irradiation unit and configured to receive the laser light emitted from the laser irradiation unit;
a carriage on which the liquid ejection head is mounted and which moves in a second direction along the nozzle surface and intersecting with the first direction;
a control unit;
The carriage is
When moving in the second direction, the nozzle passes through a determination position positioned between the laser irradiation unit and the laser light receiving unit in the first direction;
The control unit
outputting a plurality of drive signals to the liquid ejection head at a predetermined drive cycle to eject the liquid from the nozzle;
A period of time twice the drive period after the drive period for outputting the last drive signal from the final ejection time, which is the time point at which the liquid is ejected from the nozzle by the last drive signal among the plurality of drive signals. moving the carriage in the second direction so as to pass the determination position at a predetermined timing within the determination period up to the elapsed time;
irradiating the laser irradiation unit with a laser beam at the predetermined timing;
A liquid ejecting apparatus, wherein whether or not liquid overflows from the nozzle to the nozzle surface is determined based on the amount of laser light received by the laser light receiving section at the predetermined timing. The liquid ejection head is
a plurality of individual channels each including the nozzle and a pressure chamber communicating with the nozzle;
a common channel connected to the plurality of individual channels;
a plurality of driving elements provided individually for the plurality of individual channels and applying pressure to the liquid in the pressure chamber;
Let AL be the time required for the pressure wave generated in the pressure chamber by driving the driving element to propagate to the connection portion of the individual flow path with the common flow path,
where N is an integer greater than or equal to 0,
The predetermined timing is
a timing between the final ejection point and a point after [0.5×AL] has passed from the final ejection point, or
The timing is between a time point [(1.5+2×N)×AL] after the final ejection time point and a time point after [(2.5+2×N)×AL] time after the final ejection time. 2. The liquid ejecting apparatus according to claim 1. The control unit
By outputting the plurality of drive signals to the liquid ejection head while moving the carriage in the second direction, the liquid is ejected from the nozzles toward the ejection receiving medium within a predetermined ejection range in the second direction. to perform a recording pass process, which is an operation to cause
2. A determination is made as to whether or not said overflow has occurred, with a time point at which the last liquid is ejected from said nozzles toward an ejection receiving medium in said printing pass process as said final ejection time point. 2. The liquid ejecting apparatus according to 2. a cap disposed within a moving range of the carriage in the second direction and covering the nozzle;
a pump connected to the cap;
a cap switching unit that switches between a capping state in which the nozzles are covered with the cap and an uncapping state in which the nozzles are not covered with the cap;
The laser irradiation unit and the laser light receiving unit are provided on the cap,
When the control unit determines that the overflow has occurred,
3. The cap switching unit is controlled to be in the capping state, and then the pump is driven to perform a purge, which is an operation of discharging the liquid in the liquid ejection head from the nozzle. 4. The liquid ejection device according to 3. a cap disposed within a moving range of the carriage in the second direction and covering the nozzle;
a pump connected to the cap;
a cap switching unit that switches between a capping state in which the nozzles are covered with the cap and an uncapping state in which the nozzles are not covered with the cap;
The control unit
determining whether or not the overflow occurs when a predetermined flushing condition is satisfied after the printing pass process;
When it is determined that the overflow has occurred, an operation of controlling the cap switching unit to set the capping state and then driving the pump to discharge the liquid in the liquid ejection head from the nozzle. causes a purge to occur with
When it is determined that the overflow has not occurred, the liquid ejection head is caused to perform flushing, which is an operation of ejecting the liquid from the nozzles, separately from ejecting the liquid toward the ejection receiving medium. 4. The liquid ejecting apparatus according to claim 3. a liquid receptacle disposed within a range of movement of the carriage in the second direction;
wherein the cap is located on one side of the ejection range in the second direction,
the liquid receiver is positioned on the other side of the ejection range in the second direction;
As the laser irradiation unit and the laser light receiving unit,
a first laser irradiation unit and a first laser light receiving unit arranged at a position between the ejection range and the cap in the second direction, or provided on the cap;
a second laser irradiation unit and a second laser light receiving unit arranged at a position between the ejection range and the liquid receiver in the second direction, or provided in the liquid receiver;
The control unit
After the printing pass process, when the flushing condition is satisfied, the carriage is moved to the closer of the first position where the nozzles face the cap and the second position where the nozzles face the liquid receiver, whichever is closer. position and
When moving the carriage to the first position,
In a state in which the laser beam is emitted from the first laser irradiation unit, the carriage is moved at the predetermined timing so that the nozzle serving as the determination position is between the first laser irradiation unit and the first laser light receiving unit. Move it so that it passes through the position where it comes to,
determining whether or not the overflow occurs based on the amount of laser light received by the first laser light receiving unit at the predetermined timing;
When moving the carriage to the second position,
In a state in which the laser beam is emitted from the second laser irradiation unit, the carriage is moved at the predetermined timing between the nozzle serving as the determination position and the second laser irradiation unit and the second laser light receiving unit. Move it so that it passes through the position where it comes to,
6. The liquid ejecting apparatus according to claim 5, wherein whether or not said overflow has occurred is determined based on the amount of laser light received by said second laser light receiving portion at said predetermined timing. The control unit
When it is determined that the overflow has occurred based on the amount of laser light received by the first laser light receiving section, the cap switching section is controlled while the carriage is positioned at the first position. 7. The liquid ejection apparatus according to claim 6, wherein the purge is performed by driving the pump after the capping state is established. The control unit
When it is determined that the overflow has occurred based on the amount of laser light received by the second laser light receiving section, the carriage is moved to the first position, and then the cap switching section is controlled. 8. The liquid ejection apparatus according to claim 6, wherein the purge is performed by driving the pump after the capping state is established. The control unit
When it is determined that the overflow has not occurred based on the amount of laser light received by the first laser light receiving section, the carriage is kept at the first position, and the liquid ejecting head is ejected from the nozzles. performing the flushing for discharging the liquid toward the cap;
When it is determined that the overflow has not occurred based on the amount of laser light received by the second laser light-receiving portion, the carriage is kept at the second position, and the liquid ejecting head is ejected from the nozzles. 9. The liquid ejecting apparatus according to any one of claims 6 to 8, wherein the flushing is performed to eject the liquid toward the liquid receiver. a liquid receptacle disposed within the movement range of the carriage in the second direction and facing the nozzle;
The laser irradiation unit and the laser light receiving unit are provided in the liquid receiver,
The control unit
The carriage is moved to a position, which is the judgment position, where the nozzle faces the liquid receiver, the laser irradiation unit is irradiated with laser light, and the plurality of drive signals are output to the liquid ejection head. to perform flushing, which is an operation for ejecting the liquid from the nozzle toward the liquid receiver;
3. The liquid ejecting apparatus according to claim 1, wherein a determination is made as to whether or not said overflow has occurred, with a point of time at which the last liquid is ejected from said nozzle in said flushing being set as said final ejection point of time. . a cap disposed within a moving range of the carriage in the second direction and covering the nozzle;
a pump connected to the cap;
a cap switching unit that switches between a capping state in which the nozzles are covered with the cap and an uncapping state in which the nozzles are not covered with the cap;
When the control unit determines that the overflow has occurred,
The carriage is positioned at a position where the nozzles face the caps, the cap switching unit is controlled to set the capping state, and the pump is driven to move the liquid from the nozzles to the liquid discharge head. 11. The liquid ejecting apparatus according to claim 10, wherein purging, which is an operation of discharging the liquid, is performed. By outputting the plurality of drive signals to the liquid ejection head while moving the carriage in the second direction, the liquid is ejected from the nozzles toward the ejection receiving medium within a predetermined ejection range in the second direction. to perform a recording pass process, which is an operation to cause
12. The liquid ejecting apparatus according to claim 11, wherein the liquid receiver and the cap are arranged on the same side with respect to the ejection range in the second direction. 12. The liquid ejecting apparatus according to claim 11, wherein the cap also serves as the liquid receiver. a cap disposed within a moving range of the carriage in the second direction and covering the nozzle;
a pump connected to the cap;
a liquid receptacle disposed within a movement range of the carriage in the second direction;
a cap switching unit that switches between a capping state in which the nozzles are covered with the cap and an uncapping state in which the nozzles are not covered with the cap;
The control unit
By outputting the plurality of drive signals to the liquid ejection head while moving the carriage in the second direction, the liquid is ejected from the nozzles toward the ejection receiving medium within a predetermined ejection range in the second direction. to perform a recording pass process, which is an operation to cause
wherein the cap is located on one side of the ejection range in the second direction,
the liquid receiver is positioned on the other side of the ejection range in the second direction;
As the laser irradiation unit and the laser light receiving unit,
a first laser irradiation unit and a first laser light receiving unit provided on the cap;
a second laser irradiation unit and a second laser light receiving unit provided in the liquid receiver;
The control unit
After the printing pass process, when a predetermined flushing condition is satisfied, the carriage is moved to a first position where the nozzles face the cap, or a second position where the nozzles face the liquid receiver. move it closer
When the carriage is moved to the first position,
After irradiating a laser beam from the first laser irradiator, a first flushing is performed, which is an operation of outputting the plurality of drive signals to the liquid ejection head to eject the liquid from the nozzle toward the cap. let,
The overflow occurs based on the light amount of the laser beam received by the first laser light receiving portion at the predetermined timing, with the last liquid ejection time from the nozzle in the first flushing being the final ejection time. determine whether or not
When the carriage is moved to the second position,
A second flushing operation is performed by irradiating the laser beam from the second laser irradiation unit and then outputting the plurality of drive signals to the liquid ejection head to eject the liquid from the nozzle toward the liquid receiver. let it happen,
The overflow occurs based on the light amount of the laser beam received by the second laser light receiving portion at the predetermined timing, with the last liquid ejection time from the nozzle in the second flushing being the final ejection time. 3. The liquid ejecting apparatus according to claim 1, wherein a determination is made as to whether or not the liquid ejecting apparatus is The control unit
When it is determined that the overflow occurs based on the amount of laser light received by the first laser light receiving section,
With the carriage positioned at the first position, the cap switching unit is controlled to set the capping state, and then the pump is driven to discharge the liquid in the liquid ejection head from the nozzles. 15. The liquid ejecting apparatus according to claim 14, wherein a purge operation is performed. The control unit
When it is determined that the overflow occurs based on the amount of laser light received by the second laser light receiving section,
After moving the carriage to the first position, the cap switching unit is controlled to set the capping state, and then the pump is driven to discharge the liquid in the liquid ejection head from the nozzles. 16. The liquid ejecting apparatus according to claim 14, wherein a purge operation is performed. a liquid ejection head having nozzles and a nozzle surface on which the nozzles are formed;
a support member that supports the liquid ejection head;
a laser irradiation unit that is provided on the support member and that irradiates a laser beam in a first direction along the nozzle surface to a portion of the nozzle surface on which the nozzles are formed;
a laser light-receiving section provided on the support member, disposed on the opposite side of the liquid ejection head from the laser irradiation section in the first direction, and configured to receive the laser light irradiated from the laser irradiation section;
a control unit;
The control unit
outputting a plurality of drive signals to the liquid ejection head at a predetermined drive cycle to eject the liquid from the nozzle;
A period of time twice the drive period after the drive period for outputting the last drive signal from the final ejection time, which is the time point at which the liquid is ejected from the nozzle by the last drive signal among the plurality of drive signals. irradiating the laser irradiation unit with a laser beam at a predetermined timing within the determination period up to the elapsed time;
A liquid ejecting apparatus, wherein whether or not liquid overflows from the nozzle to the nozzle surface is determined based on the amount of laser light received by the laser light receiving section at the predetermined timing. a plurality of liquid ejection heads supported by the supporting member, positioned between the laser irradiation section and the laser light receiving section in the first direction, and arranged along the first direction;
a transport unit that transports the ejection target medium in a second direction that is along the nozzle surface and intersects the first direction at a position facing the plurality of liquid ejection heads. 18. A liquid ejection device according to claim 17. The control unit
An operation of ejecting liquid from the nozzles toward the ejection receiving medium by outputting the plurality of drive signals to the liquid ejection head while moving the ejection receiving medium in the second direction by controlling the transport section. to perform the ejection operation,
19. The method according to claim 18, wherein determination is made as to whether or not the overflow has occurred, with a point of time at which the last liquid is ejected from the nozzle toward the ejection receiving medium in the ejection operation as the final ejection point of time. liquid ejection device. a liquid receiver;
A first state in which the liquid ejected from the nozzles of the plurality of liquid ejection heads is received by the liquid receiver, and a second state in which the liquid ejected from the nozzles of the plurality of liquid ejection heads is not received by the liquid receiver. and a liquid receiver switching unit for switching between states,
The control unit
when liquid is to be ejected from the nozzles of the plurality of liquid ejection heads toward the ejection receiving medium, the liquid receiving switching unit is controlled to be in the second state;
When it is determined that the overflow has occurred, the liquid receiver switching unit is controlled to be in the first state, and then the liquid is directed from the nozzles of the plurality of liquid ejection heads toward the liquid receiver. 20. The liquid ejecting apparatus according to claim 18, wherein flushing for ejection is performed. a liquid ejection head having nozzles and a nozzle surface on which the nozzles are formed;
a laser irradiation unit that irradiates laser light in a first direction along the nozzle surface;
a laser light receiving unit arranged in the first direction with a gap from the laser irradiation unit and configured to receive the laser light emitted from the laser irradiation unit;
a carriage on which the liquid ejection head is mounted and which moves in a second direction along the nozzle surface and intersecting with the first direction;
a control unit;
The liquid ejection head is driven by a plurality of drive signals output from the control unit at a predetermined drive cycle to eject the liquid from the nozzles;
The carriage is
When moving in the second direction, the nozzle passes through a determination position positioned between the laser irradiation unit and the laser light receiving unit in the first direction;
A time twice the drive cycle elapses after the drive cycle of outputting the last drive signal from the final ejection time, which is the time of ejection of the liquid from the nozzle by the last drive signal among the plurality of drive signals. Passing through the determination position at a predetermined timing within the determination period up to the point in time,
In the laser irradiation unit, the control unit determines whether the liquid overflows from the nozzle to the nozzle surface based on the amount of laser light received by the laser light receiving unit at the predetermined timing. A liquid ejecting apparatus characterized by irradiating a laser beam in order to

Images